"I bought two of this power mixer a while ago. The design is fine and the product is sturdy. My major problem with it is the very low RPM produced by the electric motor used in this device, for the six AAA batteries required. I removed the shunt (protective) resistance in one of my mixers; this slightly increased the motor's RPM, but not enough to properly mix my protein shakes! The second of the 2 units I purchased is still in its box, unopened!
Overall, the low RPM and low torque of the electric motor used in this mixer makes it useless, thus my 1 star rating!"